/*
  ==============================================================================

   This file is part of the JUCE framework.
   Copyright (c) Raw Material Software Limited

   JUCE is an open source framework subject to commercial or open source
   licensing.

   By downloading, installing, or using the JUCE framework, or combining the
   JUCE framework with any other source code, object code, content or any other
   copyrightable work, you agree to the terms of the JUCE End User Licence
   Agreement, and all incorporated terms including the JUCE Privacy Policy and
   the JUCE Website Terms of Service, as applicable, which will bind you. If you
   do not agree to the terms of these agreements, we will not license the JUCE
   framework to you, and you must discontinue the installation or download
   process and cease use of the JUCE framework.

   JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
   JUCE Privacy Policy: https://juce.com/juce-privacy-policy
   JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/

   Or:

   You may also use this code under the terms of the AGPLv3:
   https://www.gnu.org/licenses/agpl-3.0.en.html

   THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
   WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

class ParameterListener : private AudioProcessorParameter::Listener,
                          private AudioProcessorListener,
                          private Timer
{
public:
    ParameterListener (AudioProcessor& proc, AudioProcessorParameter& param)
        : processor (proc), parameter (param), isLegacyParam (LegacyAudioParameter::isLegacy (&param))
    {
        if (isLegacyParam)
            processor.addListener (this);
        else
            parameter.addListener (this);

        startTimer (100);
    }

    ~ParameterListener() override
    {
        if (isLegacyParam)
            processor.removeListener (this);
        else
            parameter.removeListener (this);
    }

    AudioProcessorParameter& getParameter() const noexcept
    {
        return parameter;
    }

    virtual void handleNewParameterValue() = 0;

private:
    //==============================================================================
    void parameterValueChanged (int, float) override
    {
        parameterValueHasChanged = 1;
    }

    void parameterGestureChanged (int, bool) override {}

    //==============================================================================
    void audioProcessorParameterChanged (AudioProcessor*, int index, float) override
    {
        if (index == parameter.getParameterIndex())
            parameterValueHasChanged = 1;
    }

    void audioProcessorChanged (AudioProcessor*, const ChangeDetails&) override {}

    //==============================================================================
    void timerCallback() override
    {
        if (parameterValueHasChanged.compareAndSetBool (0, 1))
        {
            handleNewParameterValue();
            startTimerHz (50);
        }
        else
        {
            startTimer (jmin (250, getTimerInterval() + 10));
        }
    }

    AudioProcessor& processor;
    AudioProcessorParameter& parameter;
    Atomic<int> parameterValueHasChanged { 0 };
    const bool isLegacyParam;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ParameterListener)
};

class ParameterComponent : public Component,
                           public ParameterListener
{
public:
    using ParameterListener::ParameterListener;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ParameterComponent)
};

//==============================================================================
class BooleanParameterComponent final : public ParameterComponent
{
public:
    BooleanParameterComponent (AudioProcessor& proc, AudioProcessorParameter& param)
        : ParameterComponent (proc, param)
    {
        // Set the initial value.
        handleNewParameterValue();

        button.onClick = [this] { buttonClicked(); };

        addAndMakeVisible (button);
    }

    void paint (Graphics&) override {}

    void resized() override
    {
        auto area = getLocalBounds();
        area.removeFromLeft (8);
        button.setBounds (area.reduced (0, 10));
    }

    void handleNewParameterValue() override
    {
        button.setToggleState (isParameterOn(), dontSendNotification);
    }

private:
    void buttonClicked()
    {
        if (isParameterOn() != button.getToggleState())
        {
            getParameter().beginChangeGesture();
            getParameter().setValueNotifyingHost (button.getToggleState() ? 1.0f : 0.0f);
            getParameter().endChangeGesture();
        }
    }

    bool isParameterOn() const    { return getParameter().getValue() >= 0.5f; }

    ToggleButton button;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (BooleanParameterComponent)
};

//==============================================================================
class SwitchParameterComponent final : public ParameterComponent
{
public:
    SwitchParameterComponent (AudioProcessor& proc, AudioProcessorParameter& param)
        : ParameterComponent (proc, param)
    {
        for (auto& button : buttons)
        {
            button.setRadioGroupId (293847);
            button.setClickingTogglesState (true);
        }

        buttons[0].setButtonText (getParameter().getText (0.0f, 16));
        buttons[1].setButtonText (getParameter().getText (1.0f, 16));

        buttons[0].setConnectedEdges (Button::ConnectedOnRight);
        buttons[1].setConnectedEdges (Button::ConnectedOnLeft);

        // Set the initial value.
        buttons[0].setToggleState (true, dontSendNotification);
        handleNewParameterValue();

        buttons[1].onStateChange = [this] { rightButtonChanged(); };

        for (auto& button : buttons)
            addAndMakeVisible (button);
    }

    void paint (Graphics&) override {}

    void resized() override
    {
        auto area = getLocalBounds().reduced (0, 8);
        area.removeFromLeft (8);

        for (auto& button : buttons)
            button.setBounds (area.removeFromLeft (80));
    }

    void handleNewParameterValue() override
    {
        bool newState = isParameterOn();

        if (buttons[1].getToggleState() != newState)
        {
            buttons[1].setToggleState (newState,   dontSendNotification);
            buttons[0].setToggleState (! newState, dontSendNotification);
        }
    }

private:
    void rightButtonChanged()
    {
        auto buttonState = buttons[1].getToggleState();

        if (isParameterOn() != buttonState)
        {
            getParameter().beginChangeGesture();

            if (getParameter().getAllValueStrings().isEmpty())
            {
                getParameter().setValueNotifyingHost (buttonState ? 1.0f : 0.0f);
            }
            else
            {
                // When a parameter provides a list of strings we must set its
                // value using those strings, rather than a float, because VSTs can
                // have uneven spacing between the different allowed values and we
                // want the snapping behaviour to be consistent with what we do with
                // a combo box.
                auto selectedText = buttons[buttonState ? 1 : 0].getButtonText();
                getParameter().setValueNotifyingHost (getParameter().getValueForText (selectedText));
            }

            getParameter().endChangeGesture();
        }
    }

    bool isParameterOn() const
    {
        if (getParameter().getAllValueStrings().isEmpty())
            return getParameter().getValue() > 0.5f;

        auto index = getParameter().getAllValueStrings()
                                   .indexOf (getParameter().getCurrentValueAsText());

        if (index < 0)
        {
            // The parameter is producing some unexpected text, so we'll do
            // some linear interpolation.
            index = roundToInt (getParameter().getValue());
        }

        return index == 1;
    }

    TextButton buttons[2];

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (SwitchParameterComponent)
};

//==============================================================================
class ChoiceParameterComponent final : public ParameterComponent
{
public:
    ChoiceParameterComponent (AudioProcessor& proc, AudioProcessorParameter& param)
        : ParameterComponent (proc, param),
          parameterValues (getParameter().getAllValueStrings())
    {
        box.addItemList (parameterValues, 1);

        // Set the initial value.
        handleNewParameterValue();

        box.onChange = [this] { boxChanged(); };
        addAndMakeVisible (box);
    }

    void paint (Graphics&) override {}

    void resized() override
    {
        auto area = getLocalBounds();
        area.removeFromLeft (8);
        box.setBounds (area.reduced (0, 10));
    }

private:
    void handleNewParameterValue() override
    {
        auto index = parameterValues.indexOf (getParameter().getCurrentValueAsText());

        if (index < 0)
        {
            // The parameter is producing some unexpected text, so we'll do
            // some linear interpolation.
            index = roundToInt (getParameter().getValue() * (float) (parameterValues.size() - 1));
        }

        box.setSelectedItemIndex (index, dontSendNotification);
    }

    void boxChanged()
    {
        if (getParameter().getCurrentValueAsText() != box.getText())
        {
            getParameter().beginChangeGesture();

            // When a parameter provides a list of strings we must set its
            // value using those strings, rather than a float, because VSTs can
            // have uneven spacing between the different allowed values.
            getParameter().setValueNotifyingHost (getParameter().getValueForText (box.getText()));

            getParameter().endChangeGesture();
        }
    }

    ComboBox box;
    const StringArray parameterValues;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ChoiceParameterComponent)
};

//==============================================================================
class SliderParameterComponent final : public ParameterComponent
{
public:
    SliderParameterComponent (AudioProcessor& proc, AudioProcessorParameter& param)
        : ParameterComponent (proc, param)
    {
        if (getParameter().getNumSteps() != AudioProcessor::getDefaultNumParameterSteps())
            slider.setRange (0.0, 1.0, 1.0 / (getParameter().getNumSteps() - 1.0));
        else
            slider.setRange (0.0, 1.0);

        slider.setDoubleClickReturnValue (true, param.getDefaultValue());

        slider.setScrollWheelEnabled (false);
        addAndMakeVisible (slider);

        valueLabel.setColour (Label::outlineColourId, slider.findColour (Slider::textBoxOutlineColourId));
        valueLabel.setBorderSize ({ 1, 1, 1, 1 });
        valueLabel.setJustificationType (Justification::centred);
        addAndMakeVisible (valueLabel);

        // Set the initial value.
        handleNewParameterValue();

        slider.onValueChange = [this] { sliderValueChanged(); };
        slider.onDragStart   = [this] { sliderStartedDragging(); };
        slider.onDragEnd     = [this] { sliderStoppedDragging(); };
    }

    void paint (Graphics&) override {}

    void resized() override
    {
        auto area = getLocalBounds().reduced (0, 10);

        valueLabel.setBounds (area.removeFromRight (80));

        area.removeFromLeft (6);
        slider.setBounds (area);
    }

    void handleNewParameterValue() override
    {
        if (! isDragging)
        {
            slider.setValue (getParameter().getValue(), dontSendNotification);
            updateTextDisplay();
        }
    }

private:
    void updateTextDisplay()
    {
        valueLabel.setText (getParameter().getCurrentValueAsText(), dontSendNotification);
    }

    void sliderValueChanged()
    {
        auto newVal = (float) slider.getValue();

        if (! approximatelyEqual (getParameter().getValue(), newVal))
        {
            if (! isDragging)
                getParameter().beginChangeGesture();

            getParameter().setValueNotifyingHost ((float) slider.getValue());
            updateTextDisplay();

            if (! isDragging)
                getParameter().endChangeGesture();
        }
    }

    void sliderStartedDragging()
    {
        isDragging = true;
        getParameter().beginChangeGesture();
    }

    void sliderStoppedDragging()
    {
        isDragging = false;
        getParameter().endChangeGesture();
    }

    Slider slider { Slider::LinearHorizontal, Slider::TextEntryBoxPosition::NoTextBox };
    Label valueLabel;
    bool isDragging = false;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (SliderParameterComponent)
};

//==============================================================================
class ParameterDisplayComponent final : public Component,
                                        private AudioProcessorListener,
                                        private AsyncUpdater
{
public:
    ParameterDisplayComponent (AudioProcessorEditor& editorIn, AudioProcessorParameter& param)
        : editor (editorIn), parameter (param)
    {
        editor.processor.addListener (this);

        parameterName.setText (parameter.getName (128), dontSendNotification);
        parameterName.setJustificationType (Justification::centredRight);
        parameterName.setInterceptsMouseClicks (false, false);
        addAndMakeVisible (parameterName);

        parameterLabel.setText (parameter.getLabel(), dontSendNotification);
        parameterLabel.setInterceptsMouseClicks (false, false);
        addAndMakeVisible (parameterLabel);

        addAndMakeVisible (*(parameterComp = createParameterComp (editor.processor)));

        setSize (400, 40);
    }

    ~ParameterDisplayComponent() override
    {
        cancelPendingUpdate();
        editor.processor.removeListener (this);
    }

    void resized() override
    {
        auto area = getLocalBounds();

        parameterName.setBounds (area.removeFromLeft (100));
        parameterLabel.setBounds (area.removeFromRight (50));
        parameterComp->setBounds (area);
    }

    void mouseDown (const MouseEvent& e) override
    {
        if (e.mods.isRightButtonDown())
            if (auto* context = editor.getHostContext())
                if (auto menu = context->getContextMenuForParameter (&parameter))
                    menu->getEquivalentPopupMenu().showMenuAsync (PopupMenu::Options().withTargetComponent (this)
                                                                                      .withMousePosition());
    }

private:
    AudioProcessorEditor& editor;
    AudioProcessorParameter& parameter;
    Label parameterName, parameterLabel;
    std::unique_ptr<ParameterComponent> parameterComp;

    std::unique_ptr<ParameterComponent> createParameterComp (AudioProcessor& processor) const
    {
        // The AU, AUv3 and VST (only via a .vstxml file) SDKs support
        // marking a parameter as boolean. If you want consistency across
        // all  formats then it might be best to use a
        // SwitchParameterComponent instead.
        if (parameter.isBoolean())
            return std::make_unique<BooleanParameterComponent> (processor, parameter);

        // Most hosts display any parameter with just two steps as a switch.
        if (parameter.getNumSteps() == 2)
            return std::make_unique<SwitchParameterComponent> (processor, parameter);

        // If we have a list of strings to represent the different states a
        // parameter can be in then we should present a dropdown allowing a
        // user to pick one of them.
        if (! parameter.getAllValueStrings().isEmpty()
             && std::abs (parameter.getNumSteps() - parameter.getAllValueStrings().size()) <= 1)
            return std::make_unique<ChoiceParameterComponent> (processor, parameter);

        // Everything else can be represented as a slider.
        return std::make_unique<SliderParameterComponent> (processor, parameter);
    }

    void audioProcessorParameterChanged (AudioProcessor*, int, float) override {}

    void audioProcessorChanged (AudioProcessor*, const ChangeDetails& details) override
    {
        if (! details.parameterInfoChanged)
            return;

        if (MessageManager::getInstance()->isThisTheMessageThread())
            handleAsyncUpdate();
        else
            triggerAsyncUpdate();
    }

    void handleAsyncUpdate() override
    {
        parameterName .setText (parameter.getName (128), dontSendNotification);
        parameterLabel.setText (parameter.getLabel(),    dontSendNotification);

        if (auto* p = parameterComp.get())
            p->handleNewParameterValue();
    }

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ParameterDisplayComponent)
};

//==============================================================================
struct ParamControlItem final : public TreeViewItem
{
    ParamControlItem (AudioProcessorEditor& editorIn, AudioProcessorParameter& paramIn)
        : editor (editorIn), param (paramIn) {}

    bool mightContainSubItems() override { return false; }

    std::unique_ptr<Component> createItemComponent() override
    {
        return std::make_unique<ParameterDisplayComponent> (editor, param);
    }

    int getItemHeight() const override { return 40; }

    AudioProcessorEditor& editor;
    AudioProcessorParameter& param;
};

struct ParameterGroupItem final : public TreeViewItem
{
    ParameterGroupItem (AudioProcessorEditor& editor, const AudioProcessorParameterGroup& group)
        : name (group.getName())
    {
        for (auto* node : group)
        {
            if (auto* param = node->getParameter())
                if (param->isAutomatable())
                    addSubItem (new ParamControlItem (editor, *param));

            if (auto* inner = node->getGroup())
            {
                auto groupItem = std::make_unique<ParameterGroupItem> (editor, *inner);

                if (groupItem->getNumSubItems() != 0)
                    addSubItem (groupItem.release());
            }
        }
    }

    bool mightContainSubItems() override { return getNumSubItems() > 0; }

    std::unique_ptr<Component> createItemComponent() override
    {
        return std::make_unique<Label> (name, name);
    }

    String name;
};

//==============================================================================
struct GenericAudioProcessorEditor::Pimpl
{
    Pimpl (AudioProcessorEditor& editor)
        : legacyParameters (editor.processor, false),
          groupItem (editor, legacyParameters.getGroup())
    {
        const auto numIndents = getNumIndents (groupItem);
        const auto width = 400 + view.getIndentSize() * numIndents;

        view.setSize (width, 400);
        view.setDefaultOpenness (true);
        view.setRootItemVisible (false);
        view.setRootItem (&groupItem);
    }

    static int getNumIndents (const TreeViewItem& item)
    {
        int maxInner = 0;

        for (auto i = 0; i < item.getNumSubItems(); ++i)
            maxInner = jmax (maxInner, 1 + getNumIndents (*item.getSubItem (i)));

        return maxInner;
    }

    LegacyAudioParametersWrapper legacyParameters;
    ParameterGroupItem groupItem;
    TreeView view;
};

//==============================================================================
GenericAudioProcessorEditor::GenericAudioProcessorEditor (AudioProcessor& p)
    : AudioProcessorEditor (p), pimpl (std::make_unique<Pimpl> (*this))
{
    auto* viewport = pimpl->view.getViewport();

    setOpaque (true);
    addAndMakeVisible (pimpl->view);

    setResizable (true, false);
    setSize (viewport->getViewedComponent()->getWidth() + viewport->getVerticalScrollBar().getWidth(),
             jlimit (125, 400, viewport->getViewedComponent()->getHeight()));
}

GenericAudioProcessorEditor::~GenericAudioProcessorEditor() = default;

void GenericAudioProcessorEditor::paint (Graphics& g)
{
    g.fillAll (getLookAndFeel().findColour (ResizableWindow::backgroundColourId));
}

void GenericAudioProcessorEditor::resized()
{
    pimpl->view.setBounds (getLocalBounds());
}

} // namespace juce